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Kristopher L. Giles - One of the best experts on this subject based on the ideXlab platform.

  • Seasonal Occurrence and Impact of Natural Enemies of Hypera postica (Coleoptera: Curculionidae) Larvae in Iowa
    Environmental Entomology, 1994
    Co-Authors: Kristopher L. Giles, John J. Obrycki, T. A. Degooyer, Candy J. Orr
    Abstract:

    The entomopathogenic fungus Zoophthora phytonomi (Arthur), (Zygomycetes: Entomophthorales), infected populations of Hypera postica (Gyllenhal), (Coleoptera: Curculionidae), larvae at four sites in central and south-central Iowa in 1990, 1991, and 1992. Six epizootics (>50% host infection) were observed during this 3-yr study; five were associated with above average rainfall. First occurrence of disease after 1 January 1991, occurred following the accumulation of 168–207 degree days above 9°C. From 30 March to 28 May (1991), rainfall averaged between 3.6–7.0 mm per day, promoting epizootics of disease that reduced total larval populations from 15–61% at four locations in Iowa. In 1992, enzootics

  • Optimizing biotic mortality for management of the alfalfa weevil Hypera postica Gyllenhal (Coleoptera: Curculionidae)
    1
    Co-Authors: Kristopher L. Giles
    Abstract:

    15 Introduction 15 Materials and Methods 17 Results and Discussion 19 Acknowledgments 22 References Cited 22 CHAPTER 2. TRANSMISSION AND DEVELOPMENT OF ZOOPHTHORA PHYTONOMI ARTHUR (ENTOMOPHTHORALES: ENTOMOPHTHORACEAE) IN Hypera postica GYLLENHAL (COLEOPTERA: CURCULIONIDAE) LARVAE EXPOSED TO AN INSECTICIDE 27 Abstract 27 Introduction 27 Materials and Methods 29 Results and Discussion 30 Acknowledgments 32 References Cited 33 CHAPTER 3. INFLUENCE OF REDUCED INSECTICIDE RATES AND STRIPHARVESTING ON ALFALFA WEEVIL LARVAL POPULATIONS AND PREVALENCE OF ZOOPHTHORA PHYTONOMI ARTHUR (ENTOMOPHTHORALES: ENTOMOPHTHORACEAE) 38 Abstract 38 InU-oduction 39 Materials and Methods 41 Environmental Conditions 41

H. Soltani - One of the best experts on this subject based on the ideXlab platform.

F. B. Peairs - One of the best experts on this subject based on the ideXlab platform.

  • Evaluation of hymenopterous biological control agents of the alfalfa weevil larvae Hypera postica (Coleoptera: Curculionidae) in northcentral Colorado.
    Journal of the Kansas Entomological Society, 1996
    Co-Authors: Hassan Al-ayedh, B. C. Kondratieff, Sue L. Blodgett, F. B. Peairs
    Abstract:

    The alfalfa weevil, Hypera postica (Gyllenhal) is the key insect pest of alfalfa in Colorado. Hypera postica reportedly has two distinct strains in the state, the eastern strain and western strain. However, during the period of this study in Northcentral Colorado, only the western strain was found. Also, one generation of the alfalfa weevil was detected, as a spring generation with an extended summer period of larvae activity. We evaluated the hymenopterous parasitoids of the alfalfa weevil lar vae in fields with and without insecticide treatments. We recovered three larval parasitoids during this study: Bathyplectes curculionis (Thomson), B. stenostigma (Thomson), and B. anurus (Thomson). Average within-field parasitism percentage by all three species ranged between 2.9-7.1%. Highest combined parasitism by Bathyplectes spp. was 13.1%, with B. curculionis the most abundant species causing up to 5.0% mortality of alfalfa weevil larvae in some fields. Bathyplectes curculionis showed two distinct peaks of parasitism closely following H. postica larval activity in the spring and summer. Parasitism caused by B. stenostigma and B. anurus was 2.1 and

  • evaluation of hymenopterous biological control agents of the alfalfa weevil larvae Hypera postica coleoptera curculionidae in northcentral colorado
    Journal of the Kansas Entomological Society, 1996
    Co-Authors: Hassan Alayedh, B. C. Kondratieff, Sue L. Blodgett, F. B. Peairs
    Abstract:

    The alfalfa weevil, Hypera postica (Gyllenhal) is the key insect pest of alfalfa in Colorado. Hypera postica reportedly has two distinct strains in the state, the eastern strain and western strain. However, during the period of this study in Northcentral Colorado, only the western strain was found. Also, one generation of the alfalfa weevil was detected, as a spring generation with an extended summer period of larvae activity. We evaluated the hymenopterous parasitoids of the alfalfa weevil lar vae in fields with and without insecticide treatments. We recovered three larval parasitoids during this study: Bathyplectes curculionis (Thomson), B. stenostigma (Thomson), and B. anurus (Thomson). Average within-field parasitism percentage by all three species ranged between 2.9-7.1%. Highest combined parasitism by Bathyplectes spp. was 13.1%, with B. curculionis the most abundant species causing up to 5.0% mortality of alfalfa weevil larvae in some fields. Bathyplectes curculionis showed two distinct peaks of parasitism closely following H. postica larval activity in the spring and summer. Parasitism caused by B. stenostigma and B. anurus was 2.1 and <1.0%, respectively. There was a significant higher rate of parasitism by Bathyplectes spp. in fields that had been treated with insecticides compared to untreated fields.

K. Mohammadpour - One of the best experts on this subject based on the ideXlab platform.

Myron P. Zalucki - One of the best experts on this subject based on the ideXlab platform.

  • Population density and spatial distribution pattern of Hypera postica (Coleoptera: Curculionidae) in Ardabil, Iran
    Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 2011
    Co-Authors: Mona Moradi-vajargah, Myron P. Zalucki, Ali Golizadeh, Hooshang Rafiee-dastjerdi, Mehdi Hassanpour, Bahram Naseri
    Abstract:

    The alfalfa weevil, Hypera postica (Gyllenhal), feeds almost exclusively on alfalfa, Medicago sativa L. in most region of the world where forage crop is grown. It has been investigated the population density and spatial distribution of alfalfa weevil on alfalfa in Ardabil during 2010. Using a 0.25 m2 quadrate sample unit a reliable sample size was 65, with maximum relative variation of 15%. The relative variation (RV) of the primary sampling data was 13.6. The highest population density of the alfalfa weevil was recorded on 17th April. To estimate the spatial distribution pattern of this pest, data were analyzed through index of dispersion, Lloyd’s mean crowding, Morisita’s index and two regression models (Taylor’s Power Law and Iwao’s Patchiness Regression). Taylor’s model showed an aggregated distribution pattern for all life stages. Iwao’s patchiness regression indicated that larvae, adult and total life cycle had aggregated spatial distribution (tc < tt), while pupae of alfalfa weevil exhibited a random pattern. The index of dispersion and Lloyd’s mean crowding methods indicated an aggregated distribution for this insect. Spatial distribution parameters of this species are used to outline a sampling program as well as to estimate population density of H. postica development stages. Optimum sample sizes for estimates of larval density, at three levels of precision, are presented.

  • Modeling Demographic Response to Constant Temperature in Hypera postica (Coleoptera: Curculionidae)
    Journal of Economic Entomology, 2010
    Co-Authors: Babak Zahiri, Yaghoub Fathipour, Mohammad Khanjani, Saeid Moharramipour, Myron P. Zalucki
    Abstract:

    ABSTRACT Alfalfa weevil, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), is among the most destructive pests of alfalfa, Medicago sativa L., in the world. Survivorship and fecundity schedules of H. postica were investigated to characterize the population growth potential of the weevil at six constant temperatures: 11.5, 14.0, 19.0, 24.0, 29.0, and 31.5°C. Preoviposition period, oviposition period and female longevity significantly decreased with rising temperature within the temperature range tested, At the respective temperatures adult female lived an average of 294.2, 230.2, 163.6, 141.0, 84.10, and 32.9 d, with average lifetime progeny production of 470, 814, 2,209, 3,619, 2,656, and 338 eggs per female, The net reproductive rates (R0 ) were 86.9, 288.0, 869.7, 1,479.7, 989.8, and 107.8 females per female, respectively. Mean daily fecundity (Mx ) was modeled as a function of time by using both Enkegaard and Analytis models. Survivorship data (Ix ) of adult females were summarized and compared u...